👤 Roberto J Botelho

Understanding the immunopathogenesis of COVID-19 has yielded valuable insights into predicting adverse outcomes-particularly mortality. However, significant gaps persist in our comprehension of the complex interplay among the proposed pathophysiological mechanisms. Here, we aim to investigate the immunological factors associated with mortality in critically ill, unvaccinated COVID-19 patients admitted to the intensive care unit (ICU). We conducted a single-center, prospective study involving 56 unvaccinated COVID-19 patients admitted to the ICU. Plasma cytokine levels at admission were quantified using enzyme-linked immunosorbent assay (ELISA). Continuous variables were presented as median (IQR), and categorical variables as frequencies and percentages. Non-parametric tests assessed group differences. Logistic regression and receiver operating characteristic (ROC) curve analyses identified predictors of mortality, with bootstrapping (1000 re-samplings; 95 % BCa CI) applied for model validation. Deceased patients exhibited significantly higher levels of interleukin (IL)-1β, IL-2, IL-6, transforming growth factor (TGF)-β, and interferon (IFN)-γ compared to survivors. Conversely, IL-10 and IL-27 were associated with favorable outcomes. Logistic regression modeling identified elevated IL-2 and IFN-γ levels as significant predictors of mortality. Notably, individual ROC curve analyses demonstrated that IL-1β and TGF-β had excellent discriminatory ability for mortality, while IFN-γ, IL-2, and IL-27 showed very good to excellent discriminatory capacity. Our results indicate that distinct cytokine profiles differentiate survivors from non-survivors in critically ill, unvaccinated COVID-19 patients. These findings highlight the importance of cytokine dysregulation in severe COVID-19 cases and suggest potential targets for prognostic approaches. Further research is warranted to validate these results and translate them into effective clinical management strategies. Show less

Lysosome membranes contain diverse phosphoinositide (PtdIns) lipids that coordinate lysosome function and dynamics. The PtdIns repertoire on lysosomes is tightly regulated by the actions of diverse PtdIns kinases and phosphatases; however, specific roles for PtdIns in lysosomal functions and dynamics are currently unclear and require further investigation. It was previously shown that PIKfyve, a lipid kinase that synthesizes PtdIns(3,5)P Show less

Phagocytosis of filamentous bacteria occurs through tubular phagocytic cups (tPCs) and takes many minutes to engulf these filaments into phagosomes. Contravening the canonical phagocytic pathway, tPCs mature by fusing with endosomes. Using this model, we observed the sequential recruitment of early and late endolysosomal markers to the elongating tPCs. Surprisingly, the regulatory early endosomal lipid phosphatidylinositol-3-phosphate (PtdIns(3)P) persists on tPCs as long as their luminal pH remains neutral. Interestingly, by manipulating cellular pH, we determined that PtdIns(3)P behaves similarly in canonical phagosomes as well as endosomes. We found that this is the product of a pH-based mechanism that induces the dissociation of the Vps34 class III phosphatidylinositol-3-kinase from these organelles as they acidify. The detachment of Vps34 stops the production of PtdIns(3)P, allowing for the turnover of this lipid by PIKfyve. Given that PtdIns(3)P-dependent signaling is important for multiple cellular pathways, this mechanism for pH-dependent regulation of Vps34 could be at the center of many PtdIns(3)P-dependent cellular processes. Show less

In an effort to identify new alternatives for long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) supplementation, the effect of three sources of omega 3 fatty acids (algae, fish and Echium oils) on lipid profile and inflammation biomarkers was evaluated in LDL receptor knockout mice. The animals received a high fat diet and were supplemented by gavage with an emulsion containing water (CON), docosahexaenoic acid (DHA, 42.89%) from algae oil (ALG), eicosapentaenoic acid (EPA, 19.97%) plus DHA (11.51%) from fish oil (FIS), and alpha-linolenic acid (ALA, 26.75%) plus stearidonic acid (SDA, 11.13%) from Echium oil (ECH) for 4 weeks. Animals supplemented with Echium oil presented lower cholesterol total and triacylglycerol concentrations than control group (CON) and lower VLDL than all of the other groups, constituting the best lipoprotein profile observed in our study. Moreover, the Echium oil attenuated the hepatic steatosis caused by the high fat diet. However, in contrast to the marine oils, Echium oil did not affect the levels of transcription factors involved in lipid metabolism, such as Peroxisome Proliferator Activated Receptor α (PPAR α) and Liver X Receptor α (LXR α), suggesting that it exerts its beneficial effects by a mechanism other than those observed to EPA and DHA. Echium oil also reduced N-6/N-3 FA ratio in hepatic tissue, which can have been responsible for the attenuation of steatosis hepatic observed in ECH group. None of the supplemented oils reduced the inflammation biomarkers. Our results suggest that Echium oil represents an alternative as natural ingredient to be applied in functional foods to reduce cardiovascular disease risk factors. Show less